interface Person{
  name: string
  age: number

  show():void
}

class Student implements Person{
  name: string
  age: number

  constructor(name: string, age: number){
    this.name = name
    this.age = age
  }

  show(){
    console.log('I am student.')
  }
}

class Teacher implements Person{
  name: string
  age: number

  constructor(name: string, age: number){
    this.name = name
    this.age = age
  }

  show(){
    console.log('I am Teacher.')
  }
}

let s = new Student('zhagnsan', 23)
let t = new Teacher('lisi', 24)

s.show()
t.show()
